It is common to control different systems, such as control systems for heating, ventilation and air conditioning (HVAC), security, electronic access control (EAC), lighting, asset management or other facility management control systems, in various kinds of buildings.
Traditionally the HVAC, security, EAC, lighting, asset management and facility management functionalities have been controlled by separate, and hence function-based, control systems. Typically the separate control systems have been kept independent of each other. That is, all control devices associated with HVAC functionalities have been comprised in a first control system whereas all control devices associated with EAC functionalities have been comprised in a second control system. The separate control systems have often been monitored by one or more operators.
However, recently control systems linking together different control functionalities have been proposed.
International patent application WO96/22668 discloses a method of providing sensor inputs to detect occupancy in the controlled area. The method provides control signals to the lighting control system and the control signals are used to reduce the light level or turn light fixtures off at times when the area is not occupied. WO96/22668 further discloses an energy saving lighting control system for operating fluorescent light fixtures. Means for controlling the light level according to the light required for the task being done in the area is provided. A method of providing a central control of the operation of the lighting system is also provided.
However there is still need for an improved control system capable of integration of different control functionalities.